Separator



Feb. 23, 1932. E. KRAMER 1,846,209

SEPARATOR 7 Filed June 2, 1928 2 Sheets-Sheet 1 Filed June 2, 1928 2Sheets-Sheet 2 ffa/ I Patented Feb. 23, 1932 UNITED STATES ERWIN KRAMER,OF BERLIN, GERMANY, ASSIGNOR TO HARTSTOFF-METALL AKTIEN- GESELLSCHAFT,(HAMETAG) OF BERLIN-COPENICK, GERMANY SEPABATOB Application filed June2, 1928, Serial No. 282,332, and in Germany June 2, 1927.

My invention relates to a method of, and an apparatus for, operatingmills in which the material ground in the mill proper is convefyed outof the same by a blast-and is then si ted in a preliminary separator orforesifter from which the not yet sufliciently grpund material isconveyed back into said mi 1.

WVith the old apparatus of this fineness of'the sifting in the foreseparator or sifter is influenced greatly by the intensity of the blastused for conveying the ground material out of the mill. When the blastis throttled, the material conveyed out of said sifter is finer, andreversely.

My invention starts, in contradistinction to what has just been stated,from the idea to make the sifting of the material in the fore separatorpractically independent of the intensity of the blast coming from themill, and to regulate it also independently, whereby the quality of. theproduct is improved and the entire procedure is rendered more economic.Every mill grinds most economically when the already suflicientlycomminuted material is conveyed completely out of the mill immediatelyafter the desired degree of fineness has been attained so that it doesnot remain in the mill and constitutes therein an undesired ballastwhich, besides, has a detrimental effeet upon the comminution of theother particles of the material. On the other side however, it is alsoknown that when the mill is blown out a considerable portion of thematerial which has not yet been reduced to the desired fineness is alsoconveyed out of the mill. The more intense the blast is, the larger isthe amount of material conveyed unintentionally out of the mill, and themore type the diflicult is it to separate it from the other par:

ticles in the fore separator. Furthermore,

however, in the old apparatus referred to, the degree of fineness of thepowder leaving the fore-separator is diminished when the blast isintensified, and the necessity has, therefore, arisen to adjust'theblast in such a manner that the fore separator separates the materialjust at that point of time when its fineness is that desired. Thedrawback of this procedute is, however, that the complete removal of thesufficiently comminuted material is rendered questionable. Finally, theattempts to separate the fine particles and the coarse ones to asufficient degree in the fore separator have not been successful,because, sufficiently comminuted material was conveyed back from thefore separator into the mill.

Now, the present invention enables sufl'iciently comminuted material tobe conveyed out of the mill practically completely without anydetrimental det-ainmenh thereof in the mill, and to improve materiallyat the same time the separation of the coarse particles from the fineones within the fore separator. These effects are attained by regulatingthe blast used for the sifting in the fore separator independently ofthe intensity of the blast used for conveying the material out of themill. This blast can, in this way, be kept at such a degree of intensitythat the sufliiciently comminuted material is conveyed out of the millwithin practical limits instantly after the comminution has beeneffected, whereas from out of the fore separator onlythose particles I Iare conveyed which have attained the desired degree of fineness.

Another useful effect is this that the separation of the fine particlesfrom the coarse ones can be carried out far more perfectly in the foreseparator. The too long detainment of the sufficiently comminutedmaterial in the mill whereby with many kinds of material the form ofthegrain is affected in an undesired way, or the properties of thegrains are changed by heat, is considerably shortened. 35 Finally, acomminution beyond the desired degree or fineness is prevented.

The invention is particularly im ortant in connection with mills inwhich the eed opening and the.discharge opening cannot have any desiredsize. -In such mil-ls the sifting in the mill by means of the'conveyingblast can be dispensed with withoutimpairing the finenessof the materialdrawn from the fore separator.

My improved method can be carried out by means of such apparatus as areshown diagrammatically by way of example on the ac companying drawings,on which Figure 1 is a side-view, partly in section, of one embodiment,and Figure 2 a side-view, also partly viz. that on the left, at theupper end, the

in section of another embodiment. closure may be effected also atthelower end In Fig. 1, 1 denotes the casing of the mill by appropriatelyotherwise-arranged flaps or proper, and 2 and 3 are passages in the topof the like. I prefer, however, the embodiment the same. The passage 2communicates with shown in the drawings in that no particles 70 a blower4 which in turn communicates with can collect on the thus arrangedflaps.

a pipe 7 whereby the blower is connected with The intensity of the blastproduced by the a cyclone 6. Also the passage 3 is connected blower 4can be regulated or varied either by with said cyclone by a pipe 5. Thecyclone is varying suitably the number of revolutions the abovementioned fore separator. In other of the blower, or by means ofthrottling flaps 7 words, the fore separator is designed as a (notshown) or by both means. This having cyclone. The blast passes throughthe above been eil'ccted, the intensity of the air currents mentionedparts of the apparatus in this dipassing through the channels of thecasing 6 rection: 4, 2, 1. 3, 5, 6, 7 4. From the cover is determined bythe flaps 24 and which plate 8 of the fore separator is suspended a canbe closed or opened or partly opened just so casing 9 which is open atits bottom, and of as suited in the given case. The sitting oirectangular transverse section. and connected the material or particlescarried away out of at its top with a pipe 10. This pipe termithe millis determined by the velocity of the nates in another cyclone 11, fromthe top of air current or currents flowing through the which extends apipe 14 to another blower 12 casing 9, i. e. through the channel orchannels connected by abranch13 with the lower part of the same, as thecase may be; more proof the cyclone or fore separator 6. T he dicisely,the speed of the air when entering into rection of the blast produced bythis blower said channel or channels is the decisive teais as follows:12. 13, 6, 9, 10, 11, 14, 12. ture for the degree or fineness of thesitting.

The comminuted material contained in the If the speed of the air at thatplace or at those mill is conveyed out of this latter by the blastplaces is high, also coarser particles are carof the blower 4 throughthepassage 3 and the ried upward and through the casing 9, wherepipe 5 intothe fore separator 6 in which it as otherwise only finer particles areconveyed falls into the hopper-shaped lower part of through it to thecyclone 11.

the same where the particles are encountered It appears from the aboveexplanation of by the blast produced by the blower 12. e the arrangementand combination of parts already suiiicicntly comm nu ed material, i.that it is possible to adjust or determine the e. the sufficiently fineparticles, are carried fineness f th ti l conveyed i t the away by thesecond blast up into the a ing tube 10 independently of the velocity ofthe 9 and through it and the pipe 10 into the conveying blast passingthrough the tube 5,

. shown. The hopper 19 may always contain a cyclone 11 in Which latt fifine Particles and the particles conveyed to and into the of thematerial are separated from the blast cyclone 11 are th fi th m re. thfla 24 and collected in a vessel 15, whereas the blast d 25 are Open, der ly, By pening passes back to the blower 12. or closing the flaps, orthe corresponding That part of the materia which has not channelsrespectively, the sectional area of yet been suffi ien ly ('mmllhlhtedtherethe casing 9 is correspondingly altered, and

fore has not been carried upward by the blast it is lte ed just wherethe sifting chiefly of the blower 12into the casing9falls through t k slac iz, in the sifting zone proper.

a rotary conveying feeding member 16 without acting thereby upon theamount of back into the mill casing 1 through a passag the materialconveyed away from the mill.

h Casing f fi 531d member 16 The finer the particles are which arecarried made l a branch 18 and a feed away. the larger is, therefore.the sectional hopper 19, and another rotary feed member area of thesifting zone, and the sifting can arranged between the parts 19 and asbe carried out the more carefully and in a better manner.

In the simplified construction shown in Fig. 2 only one blower 12connected at one The casm 9.. 1n the to of the fore sepa a arator 6) issubdivided intd three passages or i by a f' f 'i gf y fi channels by twovertical partition walls 21 and on e )y a f h no and 22, and above thesechannels are flaps 24 cyclone 11 j h of thesame des gn as in and 25hinged to the oblique top plate 23 of The lsln'ovlded f two P the casing6. In Fig. 1 the flap 24 is in its g f f, of Whlch estdbhshes a closedposition, whereas the flap 25 is open. It mllnl atlon Wlth the feedhopper 19 and the is obvious that the blast can pass now only pipe 7 and3* establishes a connection with 1 5 through two of the three channels,and it also the pipe 5, the upper end of which comthe flap 25 wereclosed, the blast could flow municates with the fore-separator 6. A onlythrough one channel, viz. that on the chamber 28 provided in the casingenclosing righthand side of the casing 6. Instead of the fore-separatoris connected with the closing the other channels, or one of them,cyclone 11' by the pipe 10. Theway of the 0 certain store of thematerial to be comminuted in the mill.

blast is, thus, as follows: 12, 7 2, 6, 28, 10-, 11, 14-, 12*.

The dimensions of the fore separator 6" are such that the entire amountof the comminuted material conveyed into it is separated from the blastand falls down upon the oblique bottom 36 of the separator, whereas theair passes through a channel 27 into the chamber 28 in which areprovided a plurality of oblique, step-wise arranged plates 29, 30, 31,32 lying between the bottom 36 of the fore-separator and the obliquebottom 33 of the chamber 28. At its lower end 37 this chambercommunicates with a casing 38 made integral with the hopper casing andcommunicating also with the channel 2 of the mill casing 1. 16 and 20are rotary feed members corresponding to the rotary feed members of Fig.1.

The space between the bottoms 36 and 33 is subdivided into passages orchannels by the plates 2932, and the lower three of the five passages orchannels can be closed at will or as may be necessary by flaps 39, 40,41 whereby it is rendered possible to vary the sectional area betweenthe bottoms 36 and 33. The particles dribbling down from the bottom 36to the lower portion of the plate 29 and further to the lower portionsof the plate 30, 31 and 32 are subjected during this time to the actionof the blast passing from the chamber 28 into the pipe 10, and thoseparticles which the blast cannot carry away with it through the passagesbetween the oblique plates fall down into the casing 38 from which theyare conveyed back into the mill by means of the rotary feed member 16,whereas the other particles are conveyed into the cyclone 11 in whichanother separation takes place, aslhas alreTady beelrli described witrespec' 't to ig. 1. he finis ed roduct is czllected'in the vessel 15. p

In view of the size of the sectional areas as exlisting in the apparatusas actually built fer practical use the velocity of the blast passingthrough themill and the pipe 5 in order to convey the material into theforesd parator 6 is only immaterially varied by the opening or closingof one or more of the flaps 39, 40, 41. At any rate, opening a flap orthe flaps means a diminution of the resistance which the passagepresents the blast, that is .tosay, it means an increase of the speed ofthe air in the pipe in spite of the increase of the fineness of thesifting carried out at the same time.

There is in this embodiment presented a separate zone for the sittingoperation in a still better way than in Fig. 1, this zone being locatedat those places where the material slides down from the bottom 36 to theplate 29, from this to the plate 30, and so on, and it is obvious thatthe advantages claimed with respect to Fig. 1 are attained with themodification illustrated in Fig. 2 in a still higher degree.

The separation of the particles from the blast in the chamber or foreseparator 6 of Fig. 2 need by carried practically only so far that theblast passing from the fore separator into the chamber 28 does no longercontain coarser particles than are to be conveyed away through the pipe10.

It is, of course, possible to choose another number of oblique plates,such as 29-32, and another number of This depends upon the degree offineness aimed at.

I wish it to be understood that I do not limit myself to all detailsshown in the drawings. There may be departures in the details without adeparture from the essence of the invention.

I claim:

1. A separator for comminuted material comprising a casing having anoutlet opening in an upper portion thereon, a pair of pipes connected atspaced points with said casing and ada ted for connection at spacedflaps, such as 39-41.-

points, respectively, with a container for comminuted material, a blowerfor producing a circulation of air through said container and said pipesand said casing whereby comminuted material is adapted to be conveyedfrom the container to the casing by the air, means within said casingdividing the portion of the same adjacent to saidoutlet opening into aplurality of individual passa es leading to said outlet opening, andmeans or varying the effective cross sectional area of certain of saidpassages.

2. A separator for comminuted material comprising a casing having anoutlet 0 wing in an upper portion thereon, a pair 0 pipes connected atspaced points with said casing and adapted for connection at spacedpoints, respectively, with a container for com minuted material, ablower for producing a circulation of air through said container andsaid pi es and said casin whereby comminute material is adapted to beconveyed from the container to the casing by the air, means within saidcasing dividing the portion of the same adjacent to said outlet openinginto a plurality of individual passages leading to said outlet opening,and means for varying the effective cross sectional area of certain ofsaid passages, the lower portion of said casing having an outlet openingadapted for connection with the container.

In testimony whereof I aflix my signature.

ERW'IN KRAMER.

